Mass spore production of Mucor circinelloides on rice

Mucor circinelloides is a fungus that produces diverse spores throughout its life cycle. The sporangiospores, which are the most well-studied spores in this fungus, are asexual spores produced during aerial mycelial development. M. circinelloides has the potential to be used in diverse biotechnological applications. In this study, we propose rice (Oryza sativa) grains as an alternative substrate for inexpensive and large-scale sporangiospore production. The sporangiospores produced from rice and a yeast extract-peptone-glucose (YPG) medium exhibited similar protein and nucleic acid contents and phenotypes in terms of germination under different conditions and culture media, including similar virulence rates against the nematode Caenorhabditis elegans. Transgenic strains carrying self-replicative plasmids were sporulated on rice and showed plasmid stability similar to that of spores produced on the YPG medium. Approximately 20% of the spore population lost plasmids after the first passage on rice. These results reveal that rice is a suitable substrate for the mass production of sporangiospores in M. circinelloides.

Supplementary information: The online version contains supplementary material available at 10.1007/s13205-021-02853-1.